Pneumatic time compensator



March 9, 1954 E. w. PATTERSON 2,

PNEUMATIC TIME COMPENSATOR Filed Feb. 8, 1952 '5 Sheets-Sheet 2 AvraQA/aMarch 9, 1954 E. w. PATTERSON 2,671,356

PNEUMATIC TIME COMPENSATOR Filed Feb. 8, 1952 3 Sheets-Sheet 3 vA7770/QA/Ef Patented Mar. 9, l954 UNITED STATES PATENT OFFICE PNEUMATICTIME COMPENSATOR Edgar W. Patterson, Downey, Calif.

Application February 8, 1952, Serial No. 270,660

23 Claims.

The present invention is an improvement on my co-pending applicationSerial No. 129,233 for Hydraulic Time Compensator, filed November 25,1949, now Patent No. 2,651,945.

My invention relates to balancing systems for machines utilizingreciprocal motion, and more particularly to apparatus for measuring andsubsequently automatically causing the time interval to become equal forboth of the one hundred eighty degree (180) half cycles, or the up anddown or forward and backward movements of an oscillating orreciprocating machine such as an air balanced pumping unit for oil orwater wells. Such an air balanced pumping unit is disclosed in one of myprior patents, Reissue No. 20,287, March 9, 1937.

Although a balancing system such as the above mentioned one described inmy Reissue Patent No. 20,287, March 9, 937, will normally maintain asubstantially constant torque on the prime mover of an oil well pumpingunit or other reciprocating unit, changes in the load on thereciprocating member cause variations in the torque on the prime moverduring different parts of the cycle of the reciprocating unit and, thuscause variations in the time which it takes for the reciprocating unitto move through each half-cycle. These variations in th load causestresses throughout the unit which lead to a shortening of the life ofthe unit.

Consequently, it is an object of my invention to produce a timecompensator which reacts to deviations in the time intervals for thehalfcycles of a reciprocating unit in such a way that the load on one ofth half-cycles is substantially equalized to the load on the other halfcycle.

Another object of my invention is to produce a time compensator whichreacts to deviations in the time intervals of the half-cycles of an airbalanced pumping unit in such a way that the balancing pressure isadjusted to that pressure which will substantially equalize the wellload and hence equalize the time intervals of the halfcycles of thepumping unit.

Another object of my invention is to produce a time compensator whichwill automatically maintain a substantially constant torque on the primemover of an air balanced pumping unit for oil or water wells.

Another object of my invention is to produce a time compensator whichwill accurately measure the half-cycle time intervals of a reciprocatingunit and balance these time intervals in accordance with suchmeasurement.

Another object of my invention is to produce 2 a time compensator whichutilizes air to measure the half-cycles of a reciprocating unit and toactuate a balancing device in accordance with such measurement. I

Another object of my invention is to produce a pneumatic tim compensatorof the character described which can be adjusted to compensate to anypoundage over Or under a perfect balance, within reasonable values, sothat the compensator can be used for any type of pumping wherein an offbalance may be desired.

A further object of my invention is to produce a pneumatic timecompensator of the character described which may utiliz air suppliedfrom the balancing system of an air balanced pumping unit, or othersource of supply, to adjust the air pressure within said air balancingunit so that the down and up strokes of such pumping unit are properlybalanced.

Other objects and advantages of my invention will be apparent from thefollowing description and claims, the novelty consisting in the featuresof construction, combination of parts, the unique relations of themembers and the relative proportioning, disposition and operationthereof, all as is more completely outlined herein and a is particularlypointed out in the appended claims.

In the accompanying drawings, forming a part of the presentspecification,

Figure 1 is a sectional view of my invention showing both the pressurecontrol unit and the compensator unit.

Figure 2 is a side elevation, partly in section, along the line 2-2 inFigure 1, showing the details of my pressure control unit.

Figure '3 is a sectional view along the line 3-3 in Figure 1, showing myspring valve action return mechanism.

Figure 4 is a plan view of my invention.

Figure 5 is a sectional view along the line 5-5v in Figure 1.

Referring to the drawings, my pneumatic time compensator comprises twoprincipal elements, a pressure control unit I0 and a compensator unit Mypressure control unit In is primarily contained within a housing [4which in turn is secured to a compensator unit housing l6 by means ofbolts l8.

Centrally positioned within pressure control unit housing I4 is an inputshaft 20. Integrally attached to input shaft 20 by means of pins 22 and24 are a pair of annular collars. 26 and 28, respectively. Collars 26and 28 are journalled in bearings 30 and 32, respectively, to permitinput shaft 20 to freely rotate within pressure control unit housing I4.Bearing 30 is mounted within a disc 3| which is clamped in position inhousing I4 by set-screw 33.

Integrally attached to the outer end of input shaft 20 is a crank arm34, the other end of arm 34 being pivotally connected to a flexible linkcable 36 by means of crank pin 38 which is pivotally connected to thewalking beam of an oil well pumping rig, or to any reciprocal member ofa reciprocating unit which is to be balanced (not shown).

I provide a flange at one end of my collar 26 to form a clutch plate 40which is operatively connected to a second clutch plate 42 by means of aclutch facing 44 whichv may be mounted free on either of the clutchplates 40 or 42. My clutch plate 42 is freely rotatable about inputshaft 20, being mounted on bushing 46 and ball bearings 48. j 1'.-provide a constant clutch pressure on clutch facing, 44 by means ofcompression springs 41 which are compressed between collar 28 and atubularmember 49 that is slideably mounted on shaft 20. Tubular member49 transmits the constant force of springs 41 to clutch plate 42 throughbearing 48.

I, provide a pair of valve operating lugs 55. and 2 which are integrallymounted on the back of clutchplate 42. As best illustrated in Figure 2,these lugs are preferably so disposed about the centralaxis of inputshaft 20 that a straight line will intersect the tops of both lugs andthe center of input shaft 20. Lugs 50 and 52 are normally kept in theirextreme clockwise position in Figure 2 by one or more clock springs,such as clock springs 54 and 56 shown in Figure 1. One end of springs 54and 56 is aihxed to shaft 20. and the other end is anchored to a pin-.58supported by disc 3|. I maintain the correct tension in my springs 54and; 56 by adjusting disc 3 I, which may be rotated by loosening screw33.

As an alternative embodiment of my invention I sometimes provide a linkrod in place of my. flexible cable 36 to connect my crank arm 34 withthe reciprocal unit (not shown) to be balanced. In this constructionof'my invention the link rod which replaces flexible cable 36 positivelymoves the crank arm downward as well asupward, so that my return-actionclock springs 54 and 56 are unnecessary and may be omitted from thestructure.

I limit the amount of rotation of my plate 42 by an eccentric stop-slug60 which is mounted on one endof a shaft 62 that is rotatably mounted ina passage 64 in one side of my housing M. A set screw 65 in my eccentricstop-lug 60. prevents relative motion between stop-lug 60 and shaft 62.

Mounted outside of my housing l4, on the outer end of shaft 62, is acircular head 66 which is locked in position on shaft 52 by means of aset screw 68. I manually turn my circular head 66 until my eccentricstop-lug 60 is properly positioned within the housing I4 and then I lockmy circular head 66, and hence my shaft 62 and my stop-lug 60, againstrotation by tightening up a set screw 69 in my circular head 65 which isadapted to abut against the outside of housing 14.

The .upper and lower sides of my eccentric lug 60- form faces wand 12,respectively, which are adaptedato respectively engagea pairof stop- 4pins 14 and 16 that are integrally mounted on the back of my clutchplate 42.

Reciprocal motion of the walking beam or other reciprocating element(not shown) will cause reciprocation of flexible cable 36 andconsequently it will cause oscillation of crank 34 and input shaft 20.

Taking the starting point as the position shown in Figure 2, upwardmovement of flexible cable 36 will. cause upward movement of crank arm34 and hence it will causecounterclockwise movement of input shaft 2!].Clutch plate 40, which is integrally attached to shaft 20, will have thesame counterclockwise angular movement as the shaft 20.

As this counterclockwise movement of clutch plate 48 is commenced,clutch plate 42 will be moved counterclockwise because of the operativeconnection between clutch plates and 42 through the clutch facing 44.This counterclockwise movement of clutch plate 42, and the consequentraising of lug 50 and lowering of lug 52, will continue until stop-pin76 engages face 12 of eccentric stop-lug 60. This engagement of pin 16and face 12 will completely arrest the counterclockwise movement ofclutch-plate 42 and the upward and downward movement of lugs 50 and 5.2,respectively. Any further movement of shaft 26 and clutch plate 40 in acounterclockwise direction will not carry clutch plate 42, but willcause slideable engagement between clutch plates 40 and 42 throughclutch facing 44, whereby clutch plate 40 will be free to movecounterclockwise to the limit of its oscillation.

When flexible cable 36 begins to move downward in accordance withthecommencement of a new half-cycle of oscillation, shaft 25 andclutch-plate 40 immediately commence to move clockwise under theinfluence of springs 54 and 56. Plate 40 then picks up plate 42 in themanner hereinbefore described, and plate 42 will rotate clockwise untilits motion is arrested by contact between stop pin 14' and face 16 whenthe lug 50 is at its lowest point and lug 52 is at its highest point. Atthat time, there will be sliding friction between the clutch plates 40and 42, whereby clutch plate 49 will be permitted to rotate under theinfluence of springs 54 and 56 until the downward motion of cable 36ceases.

In like manner, as soon as my flexible cable 36 begins to move upwardfrom its lowest position, clutch plate 40 immediately commences to movecounterclockwise. Plate then picks up plate and the two will rotatetogether until the motion of plate 42 is stopped by contact between stoppin 16 and face 12 of stop-lug 65. Plate 40 will continue to rotatealone until its direction of rotation is reversed.

In this manner, lug will be up and lug 52 will be down for an intervalof time substantially equal to the length of time that flexible cable36*is moving from the bottom to the top of its stroke, and lug 50 willbe down and lug 52 up for an interval of time substantially equal to thelength of time that flexible cable 36 is moving from the top to thebottom of its stroke.

In order to adjust my pressure control unit It! so that the amount ofmovement of lugs 53 and 52' above a horizontal center line through shaft20'will .be exactly equal I merely loosen set screw 69 and turn circularhead 66 until faces 10, and lzof my eccentric stop-lug 66. areequidistant from the; respective stop-pins l4 and 16. Another adjustmentof eccentricstop-lugmay be made to cause one of the lugs 50 and 52 tomove farther above a horizontal line through the center of shaft 20 thanthe other lug.

I use the portion of my apparatus which I will hereinafter describe tomeasure the above two time intervals, and to readjust the balancing loadon the reciprocating unit in accordance with that measurement.

A pair of two way air valves, I3 and 88 are affixed to the top of thepressure control unit housing I4 by means of a plate 82 which is afiixedto both of valves I8 and 80 and a bolt 84 which clamps valves I8 and 90to the top of pressure control unit housing I4 by connecting saidhousing I4 and plate 82. It is to be understood that any other suitablemeans for attaching valves 78 and 80 to housing I4 may be used.

Extending downwardly from valves 78 and 80 are a pair of actuating stems86 and 83, respectively, which are slideably mounted in a pair ofsleeves 90 and 92 that are inserted in vertical passages 94 and 96through housing I4.

My two-way air valves 18 and 80 are similarly constructed, each beingprovided with a valve body 98 having a vertical bore I82 wherein atubular valve element I02 is slideably mounted. Compression springs I04are disposed within the upper portion of bores I80, being kept withinbores I09 by contact with outlet port adapters I08 which contain two-wayair ports I01 therein. Springs I04 abut against the tops of tubularvalve elements I02 and urge elements I82 downward.

Threadedly mounted in the upper portions of adapters I06 are tubularbolts I88 which contain orifices I69 and III that are adapted to controlthe amount of air which is permitted to pass into and out of two-way airvalves 18 and 80, respectively.

When valve elements I92 are in their normal positions as shown in Figure2, annular flanges III] in the upper portions of elements I82 are seatedon valve seats II2 by the downward force from springs I84. I providesealing rings I I4 between flanges IIO and valve seats I I2 to preventair from passing therethrough when flanges I I0 are seated on valveseats H2.

Still considering the position of valve elements shown in Figure 2,lower faces H6 of valve elements I02 are in contact with upper faces IIBof actuating stems 86 and 83'. Sealing rings I20 are disposed betweenfaces H6 and H8 to prevent air from passing between them when they arein contact.

By this arrangement, when my actuating stems 86 and 88 and my valveelements I02 are in the position shown in Figure 2, air will be blocked,by the seating of flanges III) on valve seats H2, from passing throughvalves 18 and 80 by entering valves I8 and 80 at air pressure inputpoints I22 and leaving valves 18 and 80 at two-way air ports I01.

A further result of this position of stems 88 and valve elements I02 isthat air will be blocked by the seating of faces H3 upon faces IIB,respectively, from passing through valves I8 and 80 by entering valvesI8 and 89 at two-way air ports I01, passing lengthwise through tubularvalve elements I02 and leaving valves I8 and 80 through bleeder passagesI24.

When lug 50 is raised and lug 52 is lowered, in the manner heretoforedescribed, my actuating stem 86 and its corresponding valve element I02are raised, and my actuating stem 88 is lowered leaving itscorresponding valve element I02 suspended, by engagement between annularflange H0 and valve seat H2, in the position shown in Figure 2. Thiswill permit compressed air to flow into valve I8 through compressed airinlet port I 22, upward through vertical bore I00, between annularflange H0 and valve seat H2 and out of valve 78 through two-way air portI01 and orifice I09. Air will be prevented from leaving valve 18 throughbleeder passage I24 by continuous engagement between face II8 ofactuating stem 86 and face H6 of the corresponding valve element I02.

At .the same time, air will be prevented from flowing through valve fromits air pressure input port I22 to its two-way air port I01 by enagement between flange H0 and seat II2 of valve 80. However, air will bepermitted to bleed through valve 80 by entering valve 80 through orificeIII and two-way air port I01, passing down through the center of tubularvalve element I02, passing between face H8 or actuating stem 88 and faceH6 of the corresponding valve element I02, and then passing out of valve80 and into the atmosphere through bleeder passage I24.

Thus, when my shaft 20 is rotated counterclockwise in Figure 2,compressed air will pass out of valve I8 through its two-way port I01and orifice I09 and air will pass into valve 80 through orifice III andits two-way port I01. Similarly, when shaft 20 is rotated clockwise inFigure 2, compressed air will ass into valve 78 through orifice I09 andits two-way port I01 and air will pass out of valve 80 through itstwo-way port I 01 and orifice III.

Compressed air may be provided at air pressure input ports I22 by aconnection between ports I22 and any conventional source of airpressure. However, in the preferred embodiment of my invention in whichmy pneumatic time compensator is utilized in connection with an airbalanced reciprocating system, main air Vessel I26 of the air balancingsystem is connected to pressure input ports I22 by means of a pressureline I28 which branches into a pair of lines I29. Since only a very lowpressure is necessary to operate my time compensator, a pressure reducerI30 is interposed in line I28.

Having explained the operation of my pressure control unit I9, I willnow describe my compensa tor unit I2. Compensator unit housing I6comprises two preferably rectangular sections, I32 and I34, havinglaterally extending flanges I36 and I38 on their respectivecircumferences. Sections I32 and I34 are so relatively positioned thatflanges I36 and I38 oppose each other, and sections I32 and I34 areclamped together by means of bolts I40.

Disposed on sections I32 and I34 of compensator unit housing I6 aretubular flanges I 42 and I44, respectively, which are centrallypositioned in inter-opposing relationship on sections I 32 and I34inside of the respective flanges I36 and I38.

Flanges I36 and I42 are connected at both the bottom and the top ofsection I32 by a centrally located vertical metal web I46, and similarlyflanges I38 and I44 are connected at both the bottom and the top ofsection I34 by a centrally located metal web I48. Metal webs I46 and I48are so disposed in sections I32 and I34 that they oppose each other.

When my compensator housing sections I32 and I34 are clamped together bybolts I40 to form the compensator housing I6 a central chamber I50 isformed inside of the tubular flanges I42 and I44. A second chamber,primary chamber I52, is formed to the right of metal webs I46 and I48between flanges I42 and I44 on the inside and flanges I36 and I38 on theoutside. A third chamber, primary chamber I54, is formed to the left ofmetal webs I46 and I48 between flanges I42 and I44 on the inside andflanges I36 and I38 on the outside.

I provide a sheet I 56 of pliable material which is clamped betweencompensator unit housing sections I32 and I34. Sheet I56 forms an airsealing gasket I58 between lateral flanges I36 and I38. A similar airsealing gasket I60 is formed by sheet I56 between tubular flanges I42and I44. Sheet I56 is perforated as at I62, between flanges I42 and I44on the inside and flanges I36 and I68 on the outside so that the rightand left hand chambers I52 and I54, respectively, remain undivided.

The portion of sheet I56 which passes through central chamber I58 formsa flexible diaphragm I64 that bisects central chamber I58 into twosecondary air chambers, I66 and I88, disposed respectively in housingsections I32 and I34.

Centrally mounted on my diaphragm I64 is a valve actuator I18 whichcomprises two portions, I12 and I14, that are clamped on opposite sidesof diaphragm I64 by means of a bolt I16. The peripheries of the twoportions I12 and I14 of actuator I18 are bevelled adjacent to diaphragmI64 to prevent injury to diaphragm I64 upon movement of the diaphragmdue to a change in the relative air pressures of chambers I66 and I68. Aplurality of stop-lugs I18. are formed on both sides of chamber I58 andextend inward toa front face I88 which is centrally positioned withinchamber I 68 and which abuts against one end of a valve actuating stem I82. Actuating stem I82 is utilized to actuate a two-way air valve I84 inmuch the same manner that my actuating stems 86 and 88 are used inconnection with my valves 18 and 80. Valve I84 is considerably moresensitive than valve 18 and 88, so that movement of actuating stem I82 asmall fraction of an inch will be sufiicient to operate valve I84.

My orifices I89 and II I, associated with valves 18 and 88,respectively, are respectively connected to right and left hand primarychambers I52 and I54 through a pair of two-way air lines I86 and I88 anda pair of two-way ports I98.

During the half-cycle of operation of the reciprocating unit which is tobe balanced when actuating stem 36 is up and actuating stem 88 is down,compressed air will flow from air vessel I26, through two-way air valveI8 in the manner heretofore explained, and hence into right-hand primarychamber I52 of the compressor unit through air line I86.

At the same time the two-way air valve 88 will permit air to flow intoit and out at bleeder passage I24, whereby air will be permitted tobleed out. of left-hand primary chamber I54 through air line I88 andtwo-way air valve 88.

I provide a small orifice I92 between my left hand primary chamber I54,and my secondary chamber I66, and a corresponding small orifice I94between my right-hand primary chamber I52 and my secondary chamber I68.

Thus, when air is permitted to flow into my right-hand primary chamberI52 by movement of actuating stem 86 to the upward position in the abovemanner, the resulting small increase of the pressure within right-handprimary chamber I52 will cause a corresponding even smaller increase inthe pressure in secondary chamber I68 due to the passage of a smallquantity of air through orifice I94.

Similarly, when air is simultaneously permitted to flow out of myleft-hand primary chamber I54 by movement of actuating stem 88 to thedownward position in the above manner, the resulting small decrease ofthe pressure within left-hand primary chamber I54 will cause acorresponding even smaller decrease in the pressure in secondary chamberI66 due to the passage of a small quantity of air through orifice I82.

By thus using my dual chamber system 0f having a pair of primarychambers I52 and I54 and a corresponding pair of secondary chambers I66and I68, I minimize the pulsation factor at diaphragm I64. This isnecessary in order to prevent constant oscillation of my actuator I18and hence of my valve actuating stem I82.

Although the preferred embodiment of my invention has this dual chambersystem, it is to be understood that my primary chambers I52 and I54 maybe omitted and suitable results will still be obtained. However, if onlya single pair of chambers, such as chambers I66 and I68, were used,these chambers I66 and I68 would have to be approximately 18 times aslarge as is necessary when I use both my primary and my secondarychambers.

Similarly, during the other half-cycle of operation of the reciprocatingunit which is to be balanced, actuating stem 86 will be down, andactuating stem 88 will be up, whereby air will be admitted to primaryand secondary chambers I54 and I66, respectively, and air will beexhausted from primary and secondary chambers I52 and I68, respectively.

The amount of air that is admitted to secondary chambers I66 and I68during the respective half-cycles depends on the amount of pressure atair pressure input ports I22, the size of the orifices I89 and III inthe two-way air lines I86 and I88, respectively, on the length of timethat the valves 16 and 88 permit air to flow to primary chambers I52 andI54, on the size of orifices I92 and I94, and the relative sizes of myprimary and secondary chambers.

The air pressure supplied to air pressure input ports I22 is maintainedat a substantially constant value by means of pressure reducer I38 inthe preferred embodiment of my invention, and since the sizes oforifices I88 and I I I, and I92 and I84 remain constant, the onlyvariable of the above factors is time.

Thus, if the half-cycles of operation of the reciprocating unit are ofidentical duration, two way air valves 18 and 88 will admit air to therespective primary chambers I52 and I54 for the same time interval andthey will also allow air to bleed out of the respective primary chambersI52 and I58 for the same time interval, whereby the .samepressure willbe maintained within each of my primary chambers I52 and I54. In turn,

this causes equal pressures to be maintained in secondary chambers I86and I68.

However, if the upward half-cycle of operation of the reciprocating unitis longer than the downward half-cycle, then two-way air valve 18 willadmit compressed air to primary chamber I 52 for a longer portion ofeach complete cycle than two-way air valve 80 will admit compressed airto primary chamber I54, and also valve 18 will permit air to bleed outof primary chamber I52 for a lesser time than valve 80 will permit airto bled out of chamber I54. In turn, this will cause a gradual increasein the air pressure within secondary chamber I08 over the air pressureWithin secondary chamber I68, whereby diaphragm I64 will move to theleft in Figure 1. This causes actuator I to move to the left as anintegral part of diaphragm I64 whereby front face I80 of actuator I18will move away from valve actuating stem I82 to the left.

On the other hand, if the downward half-cycle of operation of thereciprocating unit is longer than the upward half-cycle, air valve 80will admit compressed air to primary chamber I54 for a longer portion ofeach complete cycle than two-way air valve 18 will admit compressed airto primary chamber I52 and also valve 80 will permit air to bleed out ofprimary chamber I54 for a shorter period of time than valve 18 willpermit air to bleed out of primary chamber I52. This will cause agradual increase in the air pressure within primary chamber I54 over theair pressure within chamber I52, which in turn will cause a smallincrease in the air pressure within secondary chamber I 88 over the airpressure within secondary chamber I '68. This pressure differentialbetween secondary chambers I88 and I68 will cause diaphragm I04 andactuator I10 to move to the right in Figure 1 so that valve actuatingstem I82 will be permitted to move to the right.

Only a slight difference in the air pressures within secondary chambersI68 and I88 is necessary to cause actuation of valve actuating stem I82,but a suflicient difference in pressure is required so that merelymomentary changes in the time required for the half-cycles of thereciprocating unit will not be sufficient to actuate valve I84. The timeinterval between the first instant the reciprocating unit becomesunbalanced and when valve I84 is actuated is determined by the pressurewhich is admitted to air pressure inlet valves I22 by the sizes oforifices I88, III, I92 and I84, by the relative sizes of my primary andsecondary chambers, and by the diiference in pressure between secondarychambers I88 and I08 which is necessary order to actuate valve I84.Although the air pressure supplied at ports I22 is one of the variableswhich must be controlled, any suitable amount of pressure may be usedwhich properly corresponds with the other factors such as sizes of myorifices.

The air pressure which I supply at ports I22 may be less thanatmospheric pressure. A source of such a partial vacuum which isgenerally readily accessible is the intake manifold of a combustionengine. If the pressure at ports I22 is less than atmospheric pressure Icross my air lines I88 and I88 so that valve 18 is connected to primaryand secondary chambers I54 and I68, respectively, and so that valve 80is connected to primary and. secondary chambers I52 and I 88,respectively, This construction causes diaphragm I84 to move in the samedirection as indicated 10 above for a corresponding movement of flexiblecable 36.

Valve I84 functions similarly to valves 18 and 80, but is considerablymore sensitive to a small shift in the position of valve actuating stemI82 than valves 13 and are to movement of their respective actuatingstems 86 and 88. The outer portion of valve I84 consists of a valve bodyI93 having a small cylindrical chamber I95 in its outer end to receive acoil spring I98 and a large cylindrical chamber I98 through most of itslength which is adapted to receive the working parts of the valve.

The exposed end of spring I96 engages an annular flange 20!] of tubularvalve element 202, the outer end of valve element 202 being disposedwithin the coils of spring I96.

Shank 284 of tubular valve element 202 is slideably mounted within asleeve 206 which tightly fits in the inner portion of large cylindricalchamber I98. A sealing engagement is effected between sleeve 288 andchamber I98 by means of sealing rings 208.

Flange 200 of valve element 202 is urged into sealing engagement withvalve seat 2 I0 provided at the outer end of sleeve 208 by means of thespring I96 when the actuating stem I82 is in the position shown inFigure 1. A sealing ring 2I2 completes the seal between flange 200 andseat 2H3. In this position of valve element 202, air will not passthrough valve I84 in the usual manner by entering valve I84 at airpressure input port 2I4, passing through passages 2I6 in sleeve 208,passing along passage 2I8 provided by the reduced diameter of a portionof shank 204, passing between flange 280 and seat 2| 0 and then out ofvalve I84 through two-way air port 220.

Actuating stem I82 is slideably mounted within a sleeve 222 which iscentrally disposed through compensator unit section I34. A sealing ring224 is disposed between sleeve 222 and section I34. Stem I82 is urgedtoward actuator I10 by a coil spring 228, one end of spring 228 engaginga flanged portion 228 of stem I82 and the other end of spring 226engaging a shoulder 230 in the end of sleeve 206. I

A sealing pad 232 is aflixed to the outer end of actuating stem I82 inorder to provide a seat for the inner end 234 of tubular valve element202, so that when the actuating stem I82 and valve element 202 are inthe position shown in Figure 1, air will not be permitted to bleedthrough valve I84 by entering valve I84 through two-way air port 220,passing inward through the tubular valve element 282, passing betweensealing pad 282 and end 284 of valve element 202 and then passing out ofvalve I84 into the atmosphere through passage 288, chamber 238 andclearance 240.

When my actuating stem I82 is moved to the right in Figure 1 by movementof my actuator I10, flange 280 will become spaced from seat 2I0, wherebyair will be permitted to flow through valve I84 from air pressure inputport 2I'4 to two-way air port 220. This air is conveyed to an unloaderdevice 242 (see Figure 4) by means of an air line 244 whereby unloader242 will be so actuated as to retain the balancing pressure at the valuewhich it then has. t

On the other hand, when my actuator I10 is moved to the left in Figurel, actuating stem I82 will be moved to the left by the compression ofcoil spring 228 so that stem I82 will remain in engagement with surfaceI80 of actuator IIO. Although my spring I95 will prevent air fromentering the system through air pressure input port 2T4, air pressurewill be released from unloader 242 by being permitted to flow into valveI54 through line 244 and two-way air port 22c, through the center oftubular valve element 202, between sealing pad 232 and end 234 of valveelement202, and then pass out of valve I84 into the atmosphere throughpassage 236, chamber 238 and clearance 240. By thus removing pressurefrom my unloader 242, the unloader will permit the balancing pressure tobe raised.

It can thus be seen that whenever the upward half-cycle of thereciprocating unit becomes longer in duration than the downwardhalf-cycle, which would be the case in an oil well pumping rig when theload becomes too heavy for the balancing pressure that is being used,pressure control unit I will provide more air to chamber 168 than tochamber I65 in compensator unit I2, whereby actuator I'II! will move tothe left, so actuating my valve I84 that valve I84 will release pressurefrom unloader 242 to cause the balancing pressure to be raised.

However, whenever the reciprocating unit is in an overbalanced conditionand the downward half-cycle of the reciprocating unit is longer induration than the upward half-cycle, pressure control unit II) willprovide more air to chamber IG'B than to chamber IE8, whereby actuatorI? will move to the right, so actuating my valve I84 that valve I84 willapply pressure to unloader 242 to cause the balancing pressure to remainat the value which it then has.

Airpressure is supplied to port 2 I4 by mean of line 246 which isconnected to pressure line I28 between reducer I30 and valves I8 and 80.

I provide a set pop valve 248 in line 244 between valve IM and unloader242. Set pop valve 248 will dissipate or exhaust any excess balancingpressure from the pumping unit balancing system after a given intervalof time has elapsed from the time of introduction of the additionalpressure into the air balancing system in the manner described above. Itwill simultaneously keep suflicient air pressure from valve I84 exposedagainst un'loader 242 to maintain unloader 242 in proper operatingcondition.

The use of set pop valve 248 allows the air balancing system to be in anoverbalanced condition, after pressure is released from unloader 242through valve I84 because of a greater pressure inchamber I66 than inchamber I68, for a sufficient time to enable pressure control unit It toequalize the pressures within chambers I66 and I68. At this timeactuator I'IQ will be in its central position, as illustrated in Figure1, and set pop valve 248 will then automatically reduce the pressure inthe balancing system to the properly balanced state. Pressure controlunit III will thereafter merely maintain equal pressures within chambersI66 and I68, and valve 1 84 will remain in its normal position as shownin Figure 1.

During the normal use of my pneumatic time compensator in connectionwith a reciprocating unit I adjust eccentric stop lug 60 so that thereciprocating unit is substantially perfectly balanced. However, byproper adjustment of my eccentric stop-lug 60', I am able to compensateto any poundage over or under a perfect 'balance, within reasonablevalues. Thus, my pneumatic time compensator may be used for any 12 typeof pumping wherein either a substantially perfect balance or an offbalance is desired.

It is to be noted that although my preferred embodiment is used inconnection with an air balanced reciprocating unit, it can be connectedwith a system which is balanced by other means than air, such as apumping system which is balanced by moveable weights.

Further, it is to be understood that other devices can be used in placeof my two-way air valve I84 for enabling unloader device 242 to beactuated by movements of actuating stem I82. For example, in certainapplications of my invention wherein it may be advantageous to useelectricity instead of air as the secondary actuating medium, it wouldbe a simple matter for one skilled in the art to substitute an electricmake and break contact device for two-way air valve I84 whereby a clutchcould be moved into and out of engagement, in turn causing an aircompressor to supply and discharge air respectively precisely in thesame way that my two-way air valve I84 supplies and discharges air.

It is also to be understood that any suitable dual, two-way air valvesystem and associated operating mechanism may be utilized in place of mypreferred pressure control unit In without departing from my presentinvention.

The simplicity, accuracy and compactness of my invention contribute tomake it a highly useful and desirable commercial item.

It is to be understood that the form of my invention herein shown anddescribed is my preferred embodiment and that various changes in theshape, size and arrangement of parts may be resorted to withoutdeparting from the spirit of my invention, or the scope of the appendedclaims.

I claim:

1. A pneumatic time compensator for a reciprocating machine including apressure control unit actuated by synchronous reciprocal motion fromsaid machine, a substantially constant source of air pressure, an airpressure connection between said source of pressure and said pressurecontrol unit, a compensator unit, an air pressure connection betweensaid pressure control unit and said compensator unit and an outputmember on said compensator unit which is operatively connectable tomeans for balancing said machine.

2. A pneumatic time compensator for a reciprocating machine comprising apressure control unit including a pair of air valves actuated bysynchronous reciprocal motion from said machine, a substantiallyconstant source of air pressure, an air pressure connection between saidsource of pressure and each of said valves, a compensator unit, an airpressure connection between each of said valves and said compensatorunit and an output member on said compensator unit which is operativelyconnectable to means for balancing said machine.

3. A pneumatic time compensator for a reciprocating machine comprising apressure control unit including a pair of air valves actuated bysynchronous reciprocal motion from said machine, each of said air valveshaving an input port, an output passage and a two-way port, asubstantially constant source of air pressure, an air pressureconnection between said source of pressure and each of said input ports,a compensator unit, an air pressure connection between each of saidtwo-way ports and said compensator unit and an output member on saidcompensator unit which is operatively connectable to means for balancingsaid machine.

4. A pneumatic time compensator for a reciprocating machine including apressure control unit actuated b synchronous reciprocal motion from saidmachine, a substantially constant source of air pressure, an airpressure connection between said source of pressure and said pres surecontrol unit, a compensator unit including a pair of pressure chambers,an air pressure connection between said pressure control unit and eachof said chambers and an output member on said compensator unit which isoperatively connectable to means for balancing said machine.

5. A pneumatic time compensator for a reciprocating machine comprising apressure control unit including a pair of air valves actuated bysynchronous reciprocal motion from said machine, a substantiallyconstant source of air pressure, an air pressure connection between saidsource of pressure and each of said valves, a compensator unit includinga pair of pressure chambers, air pressure connections between said.

valves and said pressure chambers, respectively, and an output member onsaid compensator unit which is operatively connectable to means forbalancing said machine.

6. A pneumatic time compensator for a reciprocating machine comprising apressure control unit including a pair of air valves actuated bysynchronous reciprocal motion from said machine, each of said air valveshaving an input port, an output passage and a two-way port, asubstantially constant source of air pressure, an air pressureconnection between said source of pressure and each of said input ports,a compensator unit including a pair of pressure chambers, air pressureconnections between said twoway ports and said chambers, respectively,and an output member on said compensator unit which is operativelyconnectable to means for balancing said machine.

7. A pneumatic time compensator for a reciprocating machine including apressure control unit actuated b synchronous reciprocal motion from saidmachine, a substantially constant source of air pressure, an airpressure connection between said source of pressure and said pressurecontro1 unit, a compensator unit including a pair of pressure chambers,an air pressure connection between said pressure control unit and eachof said chambers, a pressure diiierential responsive member separatingsaid pressure chambers and an output member on said come pensator unitoperatively connected to said pres sure differential responsive member,said output member being operatively connectable to means for balancingsaid machine.

8. A pneumatic time compensator for a reciprocating machine comprising apressure control unit including a pair of air valves actuated bysynchronous reciprocal motion from said machine, a substantiallyconstant source of air pressure, an air pressure connection between saidsource of pressure and each of said valves, a compensator unit includinga pair of pressure chambers, air pressure connections between saidvalves and said pressure chambers, respectively, a pressure differentialresponsive member separating said pressure chambers and an. output mem--ber on said compensator unit operatively connected to said pressuredifierential responsive member, said output member being operativelyconnectable to means for balancing said machine. 9. A pneumatic timecompensator for a recip.-'

til

ro'cating machine including a' pressure control unit actuated bysynchronous motion from said machine, asubstantially constant source ofair pressure, an air pressure connection between said source of pressureand said pressure control unit,

a compensator unit including a pair of pressure" chambers, an airpressure connection between said pressure control unit and each of saidchambers, a diaphragm separating said pair of pressure chambers and anoutput member on said compensator unit operatively connected to saiddiaphragm, said output member bein operatively connectable to means forbalancing said machine.

10. A pneumatic time compensator for a reciprocating machine comprisinga pressure control unit including a pair of air valves, each of which isoperably connected to an air valve actuating stem, the respective saidactuating stem being operatively connectable, by means of a pair ofoperative connections having a substantially 180 degree relative phasediiierence, to a reciprocating member of said machine, a substantiallyconstant source of air pressure, an air pressure connection between saidsource of pressure and each of said valves, 2, compensator unit, an airpressure connection between each of said valves and said compensatorunit and an output member on said compensator unit which is operativelyconnectable to means for balancing said machine.

11. A pneumatic time compensator for a reciprocating machine comprisinga pressure control unit including a pair of air valves, each of which isoperably connected to an air valve actuating stem, the respective saidactuating stems being operatively connectable, by means of a pair ofoperative connections having a substantially 180 degree relative phasedifference, to a reciprocating member of said machine, a substantiallyconstant source of air pressure, an air pressure connection between saidsource of pressure and each of said valves, a compensator unit includinga pair of pressure chambers, air pressure connections between saidvalves and said pres sure chambers, respectively, and an output memberon said compensator unit which is operatively connectable to means forbalancing said machine.

'12. A pneumatic time compensator for a reciprocating machine includinga pressure control unit actuated by synchronous reciprocal motion fromsaid machine, a substantially constant source of air pressure, an airpressure connection between said source of pressure and said pressurecontrol unit, a compensator unit including a pair of primary pressurechambers, each of which is pneumatically connected to a respectivesecondary pressure chamber, an air pressure connection between saidpressure control unit and each of said primary chambers and an outputmember on said compensator unit which is operatively connectable tomeans for balancing said machine.

13. A pneumatic time compensator for a recip rocating machine comprisinga pressure control unit including a pair of air valves actuated bysynchronous reciprocal motion from said machine, a substantiallyconstant source of air pressure, an air pressure connection between saidsource of pressure and each of said valves,

a compensator unit including a pair of primary pressure chambers, eachof which is pneumatically connected to a respective secondary pres surechamber, air pressure connections between said valves and said primarychambers, respec tively, and an output member on said compensator unitwhich is operatively connectable to means for balancing said machine.

14. A pneumatic time compensator for a reciprocating machine including apressure control unit actuated by synchronous reciprocal motion fromsaid machine, a substantially constant source of air pressure, an airpressure connection between said source of pressure and said pressurecontrol unit, a compensator unit including a pair of primary pressurechambers, each of which is pneumatically connected to a respectivesecondary pressure chamber, an air pressure connection between saidpressure control unit and each of said primary chambers, a pressuredifferential responsive member separating said secondary pressurechambers and an output member on said compensator unit operativelyconnected to said pressure differential responsive member, said outputmember being operatively connectable to means for balancing saidmachine.

15. A pneumatic time compensator for a reciprocating machine including apressure control unit actuated by synchronous reciprocal motion fromsaid machine, a substantially constant source of air pressure, an airpressure connection between said source of pressure and said pressurecontrol unit, a compensator unit including a pair of primary pressurechambers, each of which is pneumatically connected to a respectivesecondary pressure chamber, an air pressure connection between saidpressure control unit and each of said primary chambers, a diaphragmseparating said secondary pressure chambers and an output member on saidcompensator unit operatively connected to said diaphragm, said outputmember being operatively connectable to means for balancing saidmachine.

16. A pneumatic time compensator for an air balanced reciprocatingmachine including a pressure control unit actuated by synchronousreciprocal motion from said machine, a substantially constant source ofcontrolling air pressure connected to said pressure control unit, acompensator unit, an air pressure connection between said pressurecontrol unit and said compensator unit, and an output member on saidcompensator unit consisting of a two-Way air valve.

17. A pneumatic time compensator for an air balanced reciprocatingmachine including a pressure control unit actuated by synchronousreciprocal motion from said machine, a substantially constant source ofcontrolling air pressure connected to said pressure control unit, acompensator unit including a pair of pressure chambers, an air pressureconnection between said pressure control unit and each of said chambers,a pressure differential responsive member separating said pressurechambers, an output member on said compensator unit consisting of atwo-way air valve, and an operative connection between said pressuredifferential responsive member and said two-way air valve.

18. A pneumatic time compensator for an air balanced reciprocatingmachine including a pressure control unit actuated by synchronousreciprocal motion from said machine, a substantially constant source ofcontrolling air pressure connected to said pressure control unit, acompensator unit, an air pressure connection between said pressurecontrol unit and said compensator unit, an'output member on saidcompensator unit consisting of a two-way air valve, an unloader deviceoperatively connectable .to

air balancing'means for balancing said machine, a source of unloader airpressure connected to said two-way air valve and an air connectionbetween said two-way air valve and said unloader device.

19. A pneumatic time compensator for a reciprocating machine comprisinga pressure control unit including a pair of air valves, each of which isoperably connected to an air valve actuating stem, an alternatelyrotating shaft mounted in said pressure control unit and alternatelyrotated by synchronous reciprocal motion from said reciprocatingmachine, a pair of reciprocally mounted lugs mechanicallyinterconnecting said shaft and the respective said actuating stems, asubstantially constant source of air pressure, an air pressureconnection between said source of pressure and said pressure controlunit, a compensator unit, an air pressure connection between each ofsaid valves and said compensator unit and an output member on saidcompensator unit which is operatively connectable to means for balancingsaid machine.

20. A pneumatic time compensator for a reciprocating machine comprisinga pressure control unit including a pair of air valves, each of which isoperably connected to an air valve actuating stem, an alternatelyrotating shaft mounted in said pressure control unit and alternatelyrotated by synchronous reciprocal motion from said reciprocatingmachine, a lug carrier r0- tatably mounted substantially concentricallywith said shaft, a clutch connection between said shaft and said lugcarrier to permit said shaft to oscillate at a greater amplitude thansaid lug carrier, a pair of lugs mounted on said lug carrier, anoperative connection between said lugs and the respective said actuatingstems, a substantially constant source of air pressure, anair pressureconnection between said source of pressure and said pressure controlunit, a compensator unit, an air pressure connection between each ofsaid valves and said compensator unit and an output member on saidcompensator unit which is operatively connectable to means for balancingsaid machine.

21. A pneumatic time compensator for a reciprocating machine including acompensator unit, a substantially constant source of air pressure, meansfor alternately connecting said source of pressure to said compensatorunit for substantially the time periods of the respective half cycles ofthe reciprocal motion of said machine, and an output member on saidcompensating unit which is operatively connectable to means forbalancing said machine.

22. A pneumatic time compensator for a reciprocating machine comprisinga compensator unit including a pair of pressure chambers, asubstantially constant source of air pressure. means for alternatelyconnecting said source of pressure to the respective said chambers forsubstantially the time periods of the respective half cycles of thereciprocal motion of said machine, and an output member on saidcompensator unit which is operatively connectable to means for balancingsaid machine.

23. A pneumatic time compensator for a reciprocating machine comprisinga compensator unit including a pair of pressure chambers, asubstantially constant source of air pressure, means for simultaneouslyconnecting said source of pressure to one of said chambers and opening ableed passage from the other of said chambers to the atmosphere forsubstantially the time 17 18 period of one half cycle of the reciprocalmotion of said machine and for simultaneously connect- References Citedin the file Of this patent ing said source of pressure to said last men-UNITED STATES PATENTS tioned chamber and opening a bleed passage fromsaid first mentioned chamber to the atmosphere 5 Number Name Date forsubstantially the time period of the other g ff g half cycle of thereciprocal motion of said ma- 2269787 g g e g 1942 chine, and an outputmember on said compen- 2,432,735 Downing Dec. 16, 1947 sator unit whichis operatively connectable to means for balancing said machine.

EDGAR W. PATTERSON.

